OFFSET
1,49
COMMENTS
It seems that values 11, 14, 16, 17, 18, 29, 40, 47 and 48 are completely missing (see the "bandgaps" in the scatter plot), most likely as they are also missing from A374481. Not so for 49, whose first occurrence is a(146507), where 146507 = 239*613. Note that A374481(112) = A374204(613) = A347381(613) = 49.
LINKS
FORMULA
For composite n, a(n) = Min_{d|n, 1<d<n} A347381(d).
PROG
(PARI)
A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)};
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Antti Karttunen, Jul 07 2024
STATUS
approved